Low-energy orbital excitations in strained LaCoO3 films
Low-energy orbital excitations in strained LaCoO3 films
复制标题
DOI：
10.1103/physrevb.100.165148
复制
发表时间：
2019-10
影响因子：
3.7
通讯作者：
Ru-Pan Wang;J. Geessinck;H. Elnaggar;Y. Birkhölzer;K. Tomiyasu;J. Okamoto;Boyang Liu;C. Du;D. Huang;G. Koster;F. Groot
中科院分区：
文献类型：
--
作者：
Ru-Pan Wang;J. Geessinck;H. Elnaggar;Y. Birkhölzer;K. Tomiyasu;J. Okamoto;Boyang Liu;C. Du;D. Huang;G. Koster;F. Groot
给出了应变LaCoO_3薄膜和LaCoO_3单晶的90 meV分辨Co2p~3d共振非弹性x射线散射线二色谱。在LaCoO3SrTiO3体和压应变LaCoO3LaAlO3膜上，在∼0.2 eV处观察到偏振相关的低能激发。在团簇计算的指导下，我们能够分辨出LaCoO_3体系中Co3+离子在其过渡点附近的自旋态流形。通过极化分析，我们发现自旋态可以很容易地从八面体对称的低自旋1A1g态反转到高自旋的5B2g或5Eg态，并有很小的四方形变。自旋态的混合表明，高自旋Co3+在张应变和压应变LaCoO_3薄膜的长程铁磁有序中起着重要作用。
We present 90 meV resolved Co 2 p 3 d resonant inelastic x-ray scattering linear dichroism spectra of strained LaCoO 3 films and a LaCoO 3 single crystal. A polarization-dependent low-energy excitation is observed at ∼ 0.2 eV on the tensile-strained LaCoO 3 / SrTiO 3 film, while it is not observed in either bulk LaCoO 3 or the compressive-strained LaCoO 3 / LaAlO 3 film. Guided by cluster calculations, we are able to distinguish the spin-state manifolds close to their transition point of Co 3 + ions in LaCoO 3 systems. Through a polarization analysis, we show that the spin state can easily flip from a low-spin 1 A 1 g state in an octahedral symmetry to the high-spin 5 B 2 g or 5 E g states with a small tetragonal distortion. A mixture of spin states suggests that the high-spin Co 3 + plays an important role in long-range ferromagnetic order on both tensile- and compressive-strained LaCoO 3 films.